1. Field of the Invention
The present invention pertains to call processing systems, methods and computer-based products used for telephony systems in which calls may be screened by a called party prior to connection. More particularly, the present invention is directed to voice and data systems that include Call Processors and Gateway Servers among other data communication resources, in which calls targeted for a predetermined location are directed by the programming of a Virtual Voice Network. This direction can be to any device that can be directly dialed, such as a telephone including cell phone, fax machine or modem even if the call for the targeted device is processed across the Internet, (voice or fax over Internet Protocol.)
2. Discussion of the Background
Advances in modern electronics and digital communication enable individuals to communicate virtually anywhere around the world. With the advent of cellular telephones, personal communication services, and satellite telephony, individuals in advanced as well as developing societies have an expectation of being able to communicate with others anytime and anywhere in a smooth and seamless fashion. The bulk of existing communication infrastructure is provided by local, regional and long distance telephone companies, i.e., the public switch telephone network (PSTN), which uses land lines, among other resources, for providing point-to-point communications, where each point is identifiable by a separate telephone number. For example, a caller may use a first telephone number when attempting to reach a person at the person's home, but uses a second number for contacting the person at the person's office.
A recent challenge has been how to use the PSTN, components of which contain old technology, to provide the flexibility to support people who want to remain accessible while being mobile. In light of this backdrop, some corporations use private branch exchanges (PBX) at the corporation facilities to provide "smart" functions for handling incoming phone calls (described generically here, but referring to both voice and data calls) for the convenience of its customers. Using these functions, even if an employee is not available, a properly equipped PBX enables an outside caller to be conveniently patched into voice mail, routed to another number, or perhaps transferred to a different facility in an attempt to handle the call in a user-friendly environment.
FIG. 1 is a block diagram of a conventional PSTN and PBX based system that enables a source telephone 1 to communicate with a destination telephone 11, of an intended recipient. In FIG. 1, the source telephone 1 connects to the PSTN 3 via a line (wired or wireless). The PSTN 3 recognizes the telephone number input at the source telephone 1 and provides the switch infrastructure to ultimately connect the caller with the PBX 9, which has the burden of providing the "operator" interface functions. In many cases, the corporation facilities 7 may incorporate a relay Call Processor with auto attendant functions 13 even though unit costs for such devices could exceed 1.5 million dollars in 1998. An example of such a Call Processor is an OVERTURE 300 sold by the Lucent/Octel Messaging Division.
The relay Call Processor with auto attendant 13 operates when the call is received by the PBX 9 and attempts to ring the destination telephone 11, while placing the caller on hold or utilizing any of a number of types of integration depending on the makes and models of the equipment. If the destination telephone 11 is not picked-up after a predetermined number of rings, the Call Processor with auto attendant 13 initially reports a message to the caller such as "thank you for calling company A. John Doe is on the telephone so please leave a message, dial another extension, or dial 0 for the operator." The Call Processor with auto attendant 13 is able to handle the call for the employee in this way because the PBX 9 receives and routes all telephone calls within the company facility 7 without having to interface with a variety of different local telephone equipment, each having unique signaling attributes.
For users that do not have the benefit of a corporation's PBX 9, the PSTN offers users a call forwarding operator 5 that, at the instruction of the intended recipient, forwards incoming calls to a secondary number when the intended recipient is unavailable at a primary number. This call forwarding mechanism however employs equipment at the PSTN and does not offer the same degree of convenient voice mail and auto attendant functions offered by the PBX 9 at the company facility 7.
As presently recognized by the inventor, the PBX 9 is an inherently "local" device hosted at a certain destination facility, such as a company. Available for equipment of such expense, smaller devices such as the relay Call Processor with auto attendant 13 are included with the PBX 9 to provide added functionality. Adding to the expense, the relay Call Processor with auto attendant 13 must be customized by technicians when installed at the company facility 7 so as to be compatible with the local telephone company equipment if any screened transfer types of calls were to be placed to external telephone numbers. Customization is needed because the PSTN 3 is not homogenous, but rather made up of numerous equipment of local telephone companies that may or may not have the same equipment. As an example of different signaling attributes of signals provided by typical telephone equipment, the frequency and cadence of slow-busy signals (or other signals, as will be discussed) may be substantially different from one local telephone to the next. Similarly, other signals such as a fast busy signal, indicating an error is present, differs as well.
FIG. 2 is a timing diagram of a ring/silence signal offered by exemplary local telephone company equipment. A high voltage level indicates a ring interval, while a lower voltage indicates a silence interval. For illustrative purposes, the interval "A" may typically range between a maximum tone-on (i.e., ring interval) of 1,200 ms to a minimum of 800 ms, while a typical number may be 1000 ms. The interval "B" (a silence interval) may range between 3500 ms and 2801 ms, with a typical number being 2881 ms. Interval "C" may typically range between 1200 ms and 800 ms, with a typical number being 942 ms. Interval "D" may typically range between 3485 ms and 2899 ms, with a typical number being 2910 ms. Similarly, the interval "E" may typically range between 1200 and 800 ms with a typical time 785 ms (which is less than the stated lower end of the "typical" range, but included to show that it is nonetheless a possibility). Due to this variation in cadence and frequency between signals provided by local telephone equipment, generic relay Call Processors with auto attendant functions are conventionally believed to require the use of technicians to personally customize the "application delays". This approach essentially normalizes the cadence and frequency terms so that the Call Processor can effectively interface with that particular local telephone equipment. Consequently, according to conventional wisdom, it is not believed wise, nor even possible, to use a relay Call Processor with auto attendant function in a central location that operates with different local telephone equipment because the diversity of telephone equipment does not permit the relay Call Processor with auto attendant to handle common signals in a like fashion.
FIG. 3 is a flowchart of an example method of how a caller at a source telephone 1 (FIG. 1) attempts to communicate with an intended recipient at the company facility 7. The process begins in step S1, where the caller initiates a call to the intended recipient by dialing a phone number of the company where the intended recipient is believed to be located. The process then proceeds to step S3, where the call is answered by the PBX 9 at the company facility 7, and the PBX 9 passes the call to the Call Processor with auto attendant 13. The process then proceeds to step S5, where the caller is requested to dial the extension of the intended recipient. The process then proceeds to step S7 where an inquiry is made regarding whether the individual identified at that extension is available. While making the inquiry, the Call Processor in the PBX 9 places the caller on hold and rings the destination telephone a predetermined number of times. If the intended recipient does not answer the telephone call after the predetermined number of times or if a busy signal is received, the Call Processor concludes that the intended recipient is unavailable. If the response to the inquiry in step S7 is affirmative, the PBX 9 connects the caller with the intended recipient in step S9 and the process then proceeds to step S11 where the call is completed and then the communication session ends. However, if the response to the inquiry in step S7 is negative, the process proceeds to step S13 where the relay Call Processor with auto attendant 13, audibly presents a set of options to the caller. Typical options include leaving a voice mail message, hitting zero to dial an operator or entering the extension of another party. Once the options are presented, the process proceeds to S15 where the caller selects an option and then in step S17 the selected option is executed. Subsequently the process ends. The Call Processor may also offer other options to the caller, such as attempting to contact the intended recipient at another location. If the caller chooses this option, the Call Processor with auto attendant 13 performs a blind transfer to that other location. Since the Call Processor with auto attendant 13 performs the blind transfer, the Call Processor performs no additional processing of the call even if the intended recipient is not available at the other location. The blind transfer will be made regardless; even if the called party is busy, ring no answer, error tone or dead air. Some coverage methods employ various call forwarding schemes in the event a called device is busy, or ring no answer. These methods are designed to forward the caller to a receptor mailbox. Often the receptor mailbox is located where the call originated and the called party pays the bill for any forwarding or long distance charges.
As identified by the present inventor, a limitation with conventional devices and methods is that the functions offered by the Call Processor in the PBX 9 are prohibitively expensive for the "small user". In other words, the call processing functions available at the company facility 7 are expensive to purchase and install, and thus are unsuitable for private use. Furthermore, due to differences between the different types of local telephone company equipment employed throughout the PSTN, making a conventional relay Call Processor with auto attendant available to users across a number of different local telephone company equipment is not believed to be possible, due to the different signaling attributes of the equipment employed by the different local telephone companies.
As presently recognized, the installation procedures of PBX 9 with the relay Call Processor are complex in that "hands on" customization and testing of the local telephone equipment is believed to be required in conventional systems when adjusting the destination delays for the relay Call Processor. Such difficulties are factors that contribute to the expense of purchasing and maintaining a Call Processor, even though conventional Call Processors are used over a specific geographical region sharing a common set of telephone equipment.
More centralized functions, such as call forwarding operations provided by the PSTN are incapable of detecting whether a person is available at one of the candidate locations, and "pulling back" the call for further processing if the person is unavailable. Moreover, the call forwarding operations perform a blind transfer of the call, and do not wait to determine whether the destination party will in fact receive the call. As a consequence, the user-friendliness of the call forwarding operation is presently viewed as being sub-optimal.
U.S. Pat. No. 5,375,161 describes a telephone control system with branch routing, which includes a call conferencing feature (see, e.g., FIG. 14', step 1491) that waits to determine whether or not a user may be located at another number. This technique thus employs precision busy/ring detection that requires a priori knowledge of the attributes of the local telephone communication equipment. Without this knowledge, it would not be possible for such a device to operate without significant customization of PSTN equipment at varying locations. Furthermore, the precision busy/ring would not be able to recognize an error tone, which has the same frequency as a busy but a different cadence, because the precision busy/ring unit monitors only frequency, not cadence. Cadence is a variable that fluctuates most from Central Office to Central Office. When considering a conference feature with voice, a number of conditions should be taken into consideration, including hardware sensitivity and ability to be configured, susceptibility to talk off in which the human voice emulates touch tone, and background noise. Regarding background noise, a PC modem, for example, connecting to a service provider for Internet access can cause any touch-tone activated equipment to do unexpected things. Thus, conferencing features are suboptimal.